<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div>111</div>

    <script>

        // document 属性   对象
        //   document 文档   element 元素

        console.log(document)

        console.log(document.documentElement) ;   // html标签

        document.documentElement.style.color = 'red'

        console.log(document.doctype) ;  // 文档声明

        console.log(document.head) ;

        console.log(document.body) ;

        console.log(document.title) ;   // 可读可写

        document.title = '百度一下' ;

        // console.log(document.div) ;  // 拿不到

    </script>
</body>
</html>